Miami Heat forward LeBron James watches his shot during a practice session on Wednesday at the American Airlines Arena in Miami, where the Heat will host San Antonio tonight.

MIAMI — LeBron James could not sleep after Game 6.

Imagine, then, how frayed his emotions will be going into Game 7.

So much is at stake. Legacies, for so many players, James included. The NBA championship. Whether the season was a success or a bust. How he will be portrayed over the next few months. How history will judge a Miami Heat team that won 27 straight games in one stretch, 66 games in the regular season and now 81 games overall.

Although the Heat will insist otherwise, the common belief is that it all hinges on James’ shoulders. And the four-time NBA MVP wouldn’t have it any other way when his Heat take on the San Antonio Spurs in Game 7 of the NBA Finals on Thursday night.

“I want to go down as one of the greatest. I want our team to go down as one of the greatest teams. And we have an opportunity to do that,” James said. “Hasn’t been many teams to win back-to-back championships. It’s so hard. It’s the hardest thing. I said last year it was the hardest thing I’ve ever done, winning my first. Last year don’t even come close to what we’ve gone through in this postseason and in these Finals.”

James was so weary afterward that he had trouble pulling himself up from the chair where he conducted postgame interviews. But on Wednesday, even after a night of no sleep — “everything goes through your mind after a game,” he said — James said he was already feeling more spry than he was the night before. More rest, more treatment, some time at home with family and friends and a scheduled 9 p.m. date to watch SpongeBob with his kids, James figured that was the right formula to get ready for Game 7.

His second ring is 48 minutes away. If it comes, it will be earned.

“First of all, I’m blessed, man. I don’t even know how I got here,” James said. “I wasn’t supposed to be in the NBA, if you go by statistics and things of me growing up where I grew up. Every time I go into my locker room and see the `James’ on the back of an NBA jersey, I’m like, `Wow.’ No criticism can deter me from playing this game because of that. I’m not supposed to be here.”

He means that in a more broad sense, but in simplest terms, that also applies to Thursday night.

The Heat probably aren’t supposed to be there. They were down by five points with less than a half-minute to go in regulation of Game 6. The championship celebration was being readied, literally around them. The Spurs were about to get their hands on the Larry O’Brien Trophy, and the Heat were about to slink off into another offseason of utter disappointment.

Until, of course, none of that happened.

James made a 3-pointer to get Miami within two, and after the Spurs gave Miami life by missing a free throw, Ray Allen sent it to overtime with another 3-pointer. In the extra session, James and the Heat found a way to pull out a 103-100 win, one that left Miami exhausted and San Antonio devastated. They collide one last time on Thursday with all eyes on James, who struggled for much of the game and still finished with 32 points, 10 rebounds and 11 assists.

In James’ lifetime, only four franchises — Chicago, the Los Angeles Lakers, Detroit and Houston — have won consecutive championships.

Miami can be the fifth, and even though Heat coach Erik Spoelstra is cautioning his team to not think about the potential prize, James said “human nature” dictates that he has to at least daydream a little bit about what might be looming.

“I will play Game 7 in my head from now until tomorrow night,” James said. “It’s just who I am, how I am. But I won’t be too serious. I won’t go into a bunker when I get back home. But I will be mentally sharp, mentally focused and mentally driven tomorrow night.”

For the most part, the Spurs have found a way in this series to keep James under some sort of control, and that’s even with him dropping two triple-doubles on them in six games so far.

They won’t change their approach for Game 7. And the Heat don’t expect James to change his, either. In fact, some say he’ll set the tone long before the opening tip.

“I expect LeBron to be LeBron,” Heat forward Shane Battier said. “He’s going to be loose. Usually, in shootaround, he does some dunks that would win any dunk contest if they were televised. That’s his way of saying, `OK, I’m ready to go.’ He’s going to come here, he’s going to listen to his music and he’s going to do what LeBron does. If there’s one guy we don’t have to worry about, it’s LeBron.”

James has kept his phones off during the playoffs. He’s stayed away from social media. He has tried to limit how much he hears of what the Heat call the noise, all the constant analysis of a team that has alternated wins and losses for the last month — and now needs one last two-game winning streak to wrap up their second title.

“I don’t know how it is possible,” Miller said of James turning off the outside world, as much as he can, at this time of year. “I tell him all the time, I wouldn’t want to be in his shoes. It’s not always fun being the greatest player on the planet. But he handles it about as good as I’ve ever seen anyone.”

It could be a great deal of fun for James on Thursday night.

If Miami pulls this off, a second straight Finals MVP award will likely be his, to go with the four regular-season MVPs. He’ll be a two-time champion, to go along with his two Olympic gold medals. Others have won more titles and more MVPs, but poking holes in James’ resume will become a considerably tougher task, even for his biggest naysayers.

“We can’t worry about what the history books say. That’s why it’s history,” James said. “We have to live in the present. We have to live in the moment. And we have to do whatever it takes to bring that trophy — or to keep that trophy — here in Miami.”